Propagation of Laser Generated Broadband Ultrasonic Pulses in a Thick Carbon Fibre Composite Plate

摘要

The use of laser generated ultrasound for the pulse-echo testing of carbon fibre reinforced polymer (CFRP) aerospace components is being established [1,2]. Our particular interest is in the possibility of using ultrasound propagating from the laser source along the component, as bulk or plate waves, as a means of testing a larger area for a single step in a scan. As part of an investigation into how laser generated pulses propagate in CFRP we have examined their propagation in a 40 ply, 5.5mm thick (300x300mm area) unidirectional plate. The plate was made from carbon fibre reinforced epoxy resin pre-preg (Enka Tenax HTA fibre; ICI 7716H epoxy resin). Plies were cut out by hand, laid up and then cured in a compression mould.